Composition for protecting work surfaces from contamination

ABSTRACT

A protective covering constructed from an electrostatically charged sheet having a top and bottom surface and an absorbent layer. The absorbent layer has top and bottom surfaces, the bottom surface of the absorbent layer being bonded to the top surface of the electrostatically charged sheet. The absorbent layer is divided into a plurality of cells for containing liquid spilled on the absorbent layer. The absorbent layer can be constructed from paper, open cell foam, fibrous mat, or any other absorbent material. In the preferred embodiment of the present invention, the cells are constructed by providing hydrophobic barriers in the absorbent layer. The barriers can be constructed from paraffin, plastic, or any other material that can penetrate the absorbent layer. In one embodiment of the present invention, a hydrophobic layer is bonded to the top surface of the absorbent layer. The hydrophobic layer has a plurality of pores that allow liquid spilled on the hydrophobic layer to penetrate the hydrophobic layer and be absorbed by the absorbent layer.

FIELD OF THE INVENTION

[0001] The present invention relates to electrically charged plasticsheets, and more particularly, to a self-adhering material forprotecting surfaces from contamination.

BACKGROUND OF THE INVENTION

[0002] In environments in which hazard materials such as organicsolvents and radioactive materials are used, workbenches and the likeare often covered with an absorbent disposable material to prevent thecontamination of the workbench in the event of a spill. Protectivematerials that consist of an absorbent layer with a plastic backing toprevent liquid from reaching the underlying surface are well known inthe art. Such materials are sold in rolls and are cut to the correctsize at the laboratory. The material is then secured to the workbenchwith tape to prevent the material from slipping. After the material hasserved its purpose, the material is removed by peeling off the tape, andthe material is discarded in the appropriate trash container.

[0003] This solution to the contamination problem has two problems.First, the time needed to secure the protective material to theworkbench is significant and requires the installer to have a largesupply of masking tape or the like. Second, if excessive liquid isreleased on the protective material, the absorbent layer becomessaturated, and the excess liquid can seep off of the sides of thematerial that are nearest to the saturated portion of the sheet beforethe operator can contain the spill and replace the protective layer.

[0004] Broadly, it is the object of the present invention to provide animproved protective material that can be applied to workbenches and thelike.

[0005] It is a further object of the present invention to provide aprotective material that is self-adhering, and hence, does not requiretape or other adhesives.

[0006] It is a still further object of the present invention to providea protective material that is resistant to seepage from the edges.

[0007] These and other objects of the present invention will becomeapparent to those skilled in the art from the following detaileddescription of the invention and the accompanying drawings.

SUMMARY OF THE INVENTION

[0008] The present invention is a protective covering constructed froman electrostatically charged sheet having a top and bottom surface andan absorbent layer. The absorbent layer has top and bottom surfaces, thebottom surface of the absorbent layer being bonded to the top surface ofthe electrostatically charged sheet. The absorbent layer is divided intoa plurality of cells for containing liquid spilled on the absorbentlayer. The absorbent layer can be constructed from paper, open cellfoam, a fibrous mat, or any other absorbent material. In the preferredembodiment of the present invention, the cells are constructed byproviding hydrophobic barriers in the absorbent layer. The barriers canbe constructed from paraffin, plastic, or any other material that canpenetrate the absorbent layer. In one embodiment of the presentinvention, a hydrophobic layer is bonded to the top surface of theabsorbent layer. The hydrophobic layer has a plurality of pores thatallow liquid spilled on the hydrophobic layer to penetrate thehydrophobic layer and be absorbed by the absorbent layer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a prospective view of a portion of a protective sheet 10according to the present invention.

[0010]FIG. 2 is a perspective view of another embodiment 20 of thepresent invention in which the absorbent layer may be covered with ahydrophobic plastic layer that includes pores.

DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention may be more easily understood withreference to FIG. 1, which is a prospective view of a portion of aprotective sheet 10 according to the present invention. The presentinvention utilizes a sheet 11 of electrically charged material that isbonded to a layer 12 of absorbent material. The electrically chargedmaterial is preferably a plastic that acts both as a moisture barrierand a means for securing the protective sheet to the work bench throughelectrostatic adhesion. The layer of absorbent material is preferablydivided into cells 14 by impregnating the material with a barriermaterial 13 in an appropriate pattern. The barriers prevent liquidtrapped in a cell from seeping out of the cell, and hence, solve one ofthe problems discussed above.

[0012] The barriers can be constructed from any hydrophobic materialthat can be introduced into the absorbent material. For example,paraffin can be applied at an elevated temperature to introduce waxbarriers. Similarly, varnish or other hydrophobic material can beintroduced in an appropriate solvent which is then evaporated.

[0013] The electrostatically charged sheet is preferably a plastic suchas a polyester, polycarbonate, or polypropylene. Plastic sheets of thesematerials can be charged by placing the sheets in an electric field,which is typically 10,000 volts/cm. Methods for charging such sheets arewell known to the art, and hence, will not be discussed in detail here.The sheets may be heated during the charging process to increase theremnant electric field. In the preferred embodiment of the presentinvention, a polyester film having a thickness between 0.001 inches and0.01 inches is passed between rollers and subjected to an electric fieldand corona discharge to charge the film. This film is then attached tothe absorbent layer. However, embodiments in which the film is attachedto the absorbent layer before being subjected to the electric field andcorona discharge can also be practiced.

[0014] The absorbent layer is preferably constructed from paper that hasbeen impregnated with a hydrophobic material such as paraffin. Whenplaced in contact with the plastic sheet, the stripped paper can beattached by applying an adhesive or by heating the two layers whilepressing the layers together such that the hydrophobic material meltsand acts as an adhesive. The thickness of the paper will depend on theanticipated liquid loading and the absorbency of the paper. Papercompositions such as used in paper towels are suitable for mostapplications.

[0015] The absorbent layer can also be constructed from an open cellfoam material or other absorbent material. For example, thin sheets ofplastic foam with an open cell structure can be used to provide ahigh-absorbency material. The plastic foams that can also be chargedelectrically can also be advantageously utilized. Such foams will retainmaterial electrostatically after the solution in which the material wasdissolved has evaporated from the absorbent layer, and thus, prevent theremaining material from being lost as “dust”.

[0016] Similarly, the absorbent layer can be constructed from a fibrousmat such as used in air filters. If the fibers are formed from a plasticthat can be charged, the mat can also be charged. Such electrostaticallycharged mats are well known in the air filter arts, and hence, will notbe discussed further here.

[0017] Refer now to FIG. 2, which is a perspective view of anotherembodiment 20 of the present invention in which the absorbent layer maybe covered with a hydrophobic plastic layer 21 that includes pores 22.The pores allow a liquid spilled on layer 21 to pass through to theabsorbent material while leaving the surface of the protective sheetdry. Materials such as those used in disposable diapers may be utilizedfor the top layer.

[0018] Various modifications to the present invention will becomeapparent to those skilled in the art from the foregoing description andaccompanying drawings. Accordingly, the present invention is to belimited solely by the scope of the following claims.

What is claimed is:
 1. A protective covering comprising: anelectrostatically charged sheet having a top and bottom surface; and anabsorbent layer having top and bottom surfaces, said bottom surface ofsaid absorbent layer being bonded to said top surface of saidelectrostatically charged sheet, said absorbent layer being divided intoa plurality of cells for containing liquid spilled on said absorbentlayer.
 2. The protective covering of claim 1, wherein said absorbentlayer comprises paper.
 3. The protective covering of claim 1, whereinsaid absorbent layer comprises an open cell foam.
 4. The protectivecovering of claim 3, wherein said foam is electrostatically charged. 5.The protective covering of claim 1, wherein said absorbent layercomprises a fibrous mat.
 6. The protective covering of claim 5, whereinsaid fibrous mat is electrostatically charged.
 7. The protectivecovering of claim 1, wherein said absorbent layer comprises a pluralityof hydrophobic barriers, said hydrophobic barriers defining said cells.8. The protective covering of claim 1 further comprising a hydrophobiclayer bonded to said top surface of said absorbent layer, saidhydrophobic layer having a plurality of pores therethrough, said poresallowing liquid spilled on said hydrophobic layer to penetrate saidhydrophobic layer and be absorbed by said absorbent layer.